1. Field of the Invention
The present invention relates to transportation equipment, such as convertible cargo transportation systems that can be used for transportation of bulk cargo and long cargo and more specifically to a convertible cargo transportation vehicle that enables the transportation of bulk cargo such as wood pellets and long cargo such as timber trunks.
2. Description of Related Art
In recent years, wood pellets, as special form of bulk cargo, have become an ever increasing factor in heating and energy production.
Wood pellets are part of the range of renewable energies. Wood pellets are used not only in pellet ovens and heating systems but also in powerstations to generate electricity and heating energy.
Wood pellets are in general small, often cylindrical pellets made from dried wood-chippings. In particular, wood pellets are pressed from dried wood shavings, of which two different types of primary materials are generally used. On the one hand, residual wood from sawmills is used, taking the wood chips and the sawdust, both conventionally seen as waste or by-products. On the other hand, since the increasing demand for wood pellets cannot be satisfied by this residual wood material, the processing of log becomes increasingly important. For instance, log can exist in the form of “industrial” wood which is unsuitable for sawing or raw timber trunks. Before the actual pellet manufacturing process, this log is reduced to coarse chips. Following this step, the chippings are then introduced into the pellet manufacturing process.
Besides being an environmental friendly, CO2-neutral source of energy and having a high energy density, one of the major advantages of wood pellets is their good storage and transportation properties.
However, this advantage is partly compensated by the fact that upon delivery of the wood pellets, a considerable number of empty trips results, which is both uneconomical and un-ecological.
Also from the viewpoint of a freight forwarder working in the wood pellet business, this is a very unfavorable situation.
Needless to say, these problems not only arise in connection with wood pellets. Similar problems quite general arise in connection with the transport of bulk material (e.g. sand, grain, pellets, etc.).
U.S. Pat. No. 2,761,581 A1 relates to cargo containers and more particularly to methods and apparatus whereby a string of individual cargo containers may be cooperatively loaded but individually sealed.